DESCRIPTION (Applicant's Description) Studies from our group and others have demonstrated that the risk for tobacco-related cancers differs by race, gender and type of tobacco product consumed. These important public health differences cannot be fully explained by existing patterns of tobacco consumption. We hypothesize that risk is related to the type of cigarette smoked (e.g., low versus medium yield of carcinogens), the manner in which an individual's smoking habit regulates the dosage that reaches the lungs, metabolic capacity to activate and detoxify smoke-borne carcinogens, and susceptibility to cancer related to genetic factors that may affect metabolism or DNA repair. During the first three years of the study, the program focused on epidemiology, dosage and biomarkers of dose, and metabolic pathways of carcinogen activation and detoxification. In the coming period, the former Project (epidemiology) will be replaced by an epidemiological core facility (Core C) to provide appropriate study subjects for the two continuing projects and one new project. The current Project (Dosimetry of Lung and Bladder Cancer Risk among Cigarette Smokers) is about how smoking behavior affects the "delivered" carcinogen dose, and in turn how dose is related to biomarkers of carcinogen metabolites. Project (Metabolic Epidemiology of Tobacco-Related Cancers in Black and White Americans) is a study of differences between African Americans and Caucasians in metabolic activation and/or detoxification of an array of carcinogens derived from cigarette smoking, such as NNK (a potent lung carcinogen) and 4-aminobiphenyl (a bladder carcinogen). It utilizes metabolic and molecular techniques to study pathways of activation of tobacco-derived nitrosamines related to lung cancer, which is higher in African Americans compared to Caucasians, as well as detoxification of aromatic amines involved in bladder cancer, the rate of which is lower. Project (UDP Glucuronosyltransferases, Detoxification of NNK and Lung Cancer Risk) focuses on a family of detoxification enzymes that may be related to individual risk for developing lung or bladder cancer, and for which genetic polymorphisms exist that might explain variation in cancer risk. A broader understanding of these factors, both individually and comprehensively, will contribute greatly to our understanding of the causes of tobacco-related cancers in a way that can help improve our prevention strategies. The investigators are leaders in their respective fields with a strong history of collaboration. The program is supported by an Administrative Core with an Advisory Board of distinguished scientists and a community representative, by a Biostatistics and Computing Core Facility to provide efficient data management and statistical support, and by an Epidemiology Core Facility to manage accrual of subjects, interviews, acquisition of buccal cells, urine, and blood for biomarker assays, and pathological review.